SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'daa987050c78692925ffd8a0f0c3eb99b80a712d783218ad58895e95a534ba39' 
  AND token = 'dmpaueRgDFBT/DpaFUiGTVXgK6wumDCTz6+sMumyj2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}